Dogging mechanism



G. M, PELTON 1,850,941

DOGGING MECHANISM Filed Oct, 20, 1928 41 Sheets-Sheet l March 22, l1932.

31a/manioc 6./7/242 7-0/1/ March 22, 1932. G. M. PEL-row DOGGING MECHANISM Filed Oct.

20, 1928 4 Shee'cs--SheeI 2 March'zz, 1.932.. GM PELTON. 1,850,941

DOGGING MECHANISM Filed oct. 20, 1928 4 Sheets-Sheet 5 /AQQZ G. M. FELTON March 22, 1932.

DOGGING MECHANI SM Filed Oct. 20. 1928 4 Sheets-Sheet 4 Patented Mar. 22, 1932 unire-nf sra "rr-:,s

GEORGE M. PELTOMOEMILWAUKEE, wrsconsrir, Assrcino'itfiorirerinnnfafsrownm oo., or MILWAUKEE, 'wIsconsIir A conronarron or WISCONSIN smear emes.

noeeING MnoHANIsM Application inea october'eo, was. serial NoLeiaszo'.'

This invention-relates vto dogging mecha nism for use in connection with the knees of asaw millcarriafge and particularly to specie improvements in that type oi such mechanism wherein the dogs may be adjusted relative lto the face of the knee and such-dogs areadapted for successive operativeV movementthr'o'ugh the samepower means.

rlhisapplication is filed as a'continuation if in partici' my application tiled May 19, 1927,

Serial No. 192,723, for saw -mill dogging means.

ls/iechanism of this'type is in actual practice necessarily 'of a more or less .cumbersome nature towithstand the strains of the work in hand and Vsuch mechanism has been heretofore mounted on but wholly at one side of the knee, with a consequent tendency to unbalance the knee to some extent, and further involving the projection of the added parts beyond the side of the knee with the almost certain liability -o providingfan undesirable obstruction, and at best presenting-'a comparatively crude :and unsightly appearance;

A characteristic yand important feature of the present invention is the disposition of the dogs; land thefdirect Ameans Jforpositioning the dogs relative to the face of the'knee and for operating the dogs in their engagement with the log, is arranged wholly within the normal outline of the knee, that is, between' what may be termed the side Walls thereof and substantially centrally of the knee to thereby eliminate the 4overbalancing tendency of such parts; and to place such partsr in the most effective positions in connection with Aclogging a log and. avoid the projection of such parts beyond theV side oi the knee.

A further Aobject of the invention is the provision of iiuid pressure `means for operating'the dogs' to and` from clogging relation wherein, through the useoi dilierential pressure surfaces, fthe `loss of pressure medium is restricted to a minimum and the control of such pressure medium is materially simplified.

A iurther object of the present invention is the-provision 'oimeans for adjusting the'dogsf in :their projection'beyond the' faceoithe' knee 'through "a fluid pressure mea-ns `involvv differential pistons controlledthrough d such differential pressure surfaces, witha minimum loss of motive iiuid'and :a material simplification of the control of such ilu-id.

A further object of'vthe invention is the particular construction of the :crank connection through which the dogl carrying bar is' adjusted in order tha-t eXcessivewear and flostrnotion in the parts may be reduced to 'fantin-r` nnum. Y f

Y A further objectof'the invention is tb sim# pliiy the constru'ctionand arrangement"oi" certain necessary parts of the apparatusin order to avoid complication in construction and operation, and "permit the use oth'e'av-ie'r' appropriate wear and 'strain resisting 'ma-tel' rial which, if arranged entirely beyond the' knee, would` be objectionable through its Vover'- balancing influence and itsy `Obst'ructi've'"arrangement. y

The invention is yillustrated in the'acco'mpanying drawings, in'which: p, V

Figure lv is 'a View in' vertical section through `the knee, partly broken away, the; upper dogs being shown at their downward limit, and both upper dogs at their :inner :poi sition relative to the face of the knee. Y

Figure 2 is afront view of the same: v

Figure 3 is a sectiononf line '3-3 ofFigure 1.V i

Figure 4 is a perspectiveview showing-the y 1 the relation of theknee and rack bar, :and

illustrating particularlyv the `.opening iin the knee bottom to receive the lower dog. Figure 7 isa broken perspectiveiofthe rac bar showing the latter recessed to permit Ythe necessarymovement of the lower dog.

Figure 8 is a detailfin elevationshowing 'a' modified mounting for the lower -d0g,'f :dei-1 signed particularly fo'r use in connectionwith rack and'pinion mechanism for the knee. Y Figure 9 is -a brokenelevation illust-rating? a further type'of movable lower dog. n Y f Figure 10 is a view in elevatiompartly vin section, illustrating the means for moving the guide bar in and relative to the knee.

Figure 11 is a plan of the cylinder for operating the dogs to and from clogging position.

Figure 12 is a vertical sectional view of the same.

Figure 13 is an enlarged sectional det-ail illustrating particularly the preferred form of cushioning or resilient support for the lower dog unit casting.

Figure 14 is a perspective view showing the crank mounting for the dog carrying bar.

rlhe knee 1, aside from the specific details hereinafter specifically referred to, is of conventional form with its forward portion of greatest height, the forward wall 2 of which portion constitutes the face of the knee and is provided with the usual removable wear plates 3. The side walls 4 of the knee are, in the conventional form of knee, spaced apart and the face 2 is longitudinally divided to deline a narrow space 5 of materially less width than the space between the side walls of the knee. The space between the side walls 4 of the knee forwardly7 of the rear reduced portion 6 of the knee, is utilized for the reception of the dog operating mechanism of this invention, from which it will be apparent that such mechanism is without overbalancing effect on the knee, and, except in the operating means for adjusting the dogs relative to the face of the knee, avoids any projection and therefore obstruction beyond the side wall of the knee.

The dog operating mechanism is mounted for movement on and relative to a guide bar which extends vertically of the knee between the side walls, with said guide bar mounted for selective movement toward and from the face of the knee. rlfhe means for mounting the guide bar includes upper and lower crank members each involving a crank shaft 8 adapted to be mounted in bearings 9 in the knee with the inner ends of the crank shafts provided with crank arms 10 and the outer ends with right angled crank arms which include arms 11 projecting from the crank shaft in the same direction and duplicating the crank arms 10 and additional arms 12 extending at right angles to the arms 11. The terminals of the arms 10 and 11 are formed as bearings to receive a crank pin 13 rigidly secured in and extending at right angles to the guide bar 7 near the respective ends thereof, the crank pins, for example, having a driving fit in anopening in the guide bar and being riveted in place. Beyond the crank arm 11, the crank pins 13 are terminally threaded for the reception of nut 13 to take np play.

The arms 12 of the right angled crank arms are connected by a bar 12 to compel simultaneous movement of the cranks, one of said arms 12 being extended beyond its connection f' with the bar 12 to provide for the connection thereto of a piston rod 14 operating in a cylinder 15 pivotally supported on a bracket 16 projecting from one side wall of the knee. The cylinder 15 is made up of upper and lower sections 17 and 18, the latter' being of less diameter than the former and the sections adjacent their juncture being formed with a lower ground valve seat 19 at the lower end of the section 17 and an upper ground valve seat 20 at the upper end of the section 18.

Upper and lower pistons 21 and 22 are mounted in the respective cylinder sections with suitable packing rings to prevent leakage. The pistons are connected by a rod 23 and the upper piston is connected to the piston rod 14. The upper piston is formed at its lower end, as at 24, to cooperate with seat 197 and the lower piston 22 is formed at its Lipper end, as at 25, to cooperate with seat 20.

Leakage openings 26 to permit the escape of air between the pistons as the latter are operated are formed in the lower end of the upper section 17. The section 17 is formed at the upper end with an offset 27 in which is formed a port 28 leading directly into the section 17 of the cylinder, the port opening slightly below the upper end of the section and in direct line with a fluid pressure pipe 29 removably connected in the offset.

The odsetis further formed with a by-pass 30 communicating at one end with the port 28 and leading to and above the piston 21 when the latter is at its upper limit of movement, it being understood that such piston is held in Contact with the extreme upper end of the closure for the section 17, as particularly illustrated in Figure 10. The by-pass 3U has a downwardly closing valve 31, preferably of the ball type, to prevent back pressure.

The lower end of the section 18 is formed with an offset 32 having a port 33 leading into the lower section above the lower end thereof with which a fluid pressure pipe 34 directly communicates, the offset 32 having a by-pass 35 opening into the section 18 below the extreme lower position of the piston 22, Lthis by-pass having a valve 36 closing against return pressure.

It will be understood that, by reason of the increased area of the piston 21 as compared with the piston 22, the piston rod will move downwardly under pressure fluids of substantially the same pressure delivered through pipes 29 and 34, and advantage is taken of this fact in order to save loss of pressure fluid, ordinarily air under pressure, in the operation of the device.

Thus, it will be apparent that with the air under pressure maintained constantly in the pipe 34, the movement of the piston rod and thereby the adjustment of the dog carrying bar may be controlled through a single valve manipulation governing the pressure through the pipe 29. lf pressure is admitted throughV space in section 17 above the piston`21, whereupon the constant pressure below the piston 22 will move the piston rod upwardly. There is thus no loss or exhaustion of the pressure fluid below the piston 22 at any time, the loss being reduced to a- Vminimum in that Y the pressure fluid above the piston 21 is the only pressure fluid exhausted to the atmosphere. Y

` t will of course be apparent that as either piston moves to its operative position, that is, the lower position of the upper piston or the upper position of the lower piston,'the respective pistons act to seal against the loss of pressure medium, the upper piston, when serving as a power piston through cooperation of its ground face 24 with the seat `19, sealing against the loss of pressure into `the space between the pistons, the lower piston, when in its upper opposite position, correspondingly sealing against loss of'pressure medium throughcooperation of its ground face 25 with `the seat Q0.

Thus, the cylinder and pistons for adjustp ing the dog carrying bar may be operated to move the vbar to either of its adjusted positions, that is, for maximum or minimum projection of the dogV beyond the face of the knee, through a single valve control and ith the minimum loss of motive fluid.'Y

In order to avoid excessive wear and resultant lost motion in the parts, Athe crank shafts 8 and terminal arms 10, 11 and 12 are' formed integrally, that is to say, as a solid forging. The bearing of the pins 13-in the terminals of the crank arms permitsl the necessary relative movement in the operation and any play in this movement may to a larOe extent be compensated for byadjust-- meiit of the terminal nut 13. j

rlhe clogging means proper is mounted in independent units, one including the upper dog or dogs and the other including'v the lower dog. These units are mounted for independent sliding movement on the guide bar 7, and are adapted to be operated in their log engaging stroke in succession through a single power' means, said power means, dog mountings and connections being arranged wholly within the knee, that is, between the side walls 4 thereof.`

The lower dog casting includes a cylinder 39 which is provided, in the preferred form as illustrated in Figure 1, with an offset dash-pot cylinder `40having a bleed opening 41 about `centrally of the height ,thereof and a duct 42 of gradually reduced'ffdepth upend of the dash-pot cylinder. A piston 43 is operative'in the cylinder having a piston rod 44 depending therefrom and guided in a disk 45 threaded'into `the lower end of the cylinder 40. As will later appear, this dash-pot serves tofcushion and'resiliently support the parts in operation. The cylinder 39` is -formed diametrically with a radially extending plate'4', having its vertical edges formed to, present rabbeted guide flanges 47, cooperating with similarly formed edges 48 of the guide bar 7.A The lower dog 49, otherwise of'conventional form, isv secured at50 on the plate 46, said dog extending ofcourse forwardly ofthe plate. The rear end of the dog 49 is seated in an appropriately formed opening 51 'formed in an enlargement 52 of the base 37.

The' upper dog -unit comprises a guide j plate 53', the vertical edges of which are provided for an appropriate length from the up- I per and lower ends of the plate. with guide 55, formed to slidably coop-` flanges 54 and erat'e with the described edges of the guide bar 7. That portion of the guide plate between the flanged upper and lower ends is formed on itsinner edge with a laterally directed flange 56,- the outer or free surface ofwhich is in alignment with the upper and lower flanges at such inner edge of the plate. This construction provides a square abutment throughout the length ofthe plate for a purpose which will later appear.

The plate 53 is provided at the upper inner edge with a laterally projected ear 57 which, as evident from Figure 4, is in alignmentwith the circular base V37 of the lower dog unitcasting. The surface of the plate 53, overlying the guide bar 7, is formed in that area provided with the guide flanges 54 and 55 with plate sections 58 and 59 of substantially identical construction. These plate sections are integral with the plate 53 and have a width at their lower ends somewhat less than that of the plate 53, and are gradually decreased in width toward their upper ends. These' plate sections, except at their extreme upper ends, are in spaced parallel relation to the plate 53,and provide with that plate 'what may betermed a dog guiding means. The plate sections are connected to the plate 53 at their inner or rear walls, the latter extending laterally from the plate 53, and being coincident with the flange 56 to vertically extend the` abutment formed by that flange. Y i

The eXtreme upper ends of the plate sections 58 and 59 are of increased-thickness, permitting an'integral construction at this 'point as an additional support yfor theplate wardly leading from the to the upper i tions by pivot pins 6l mounted at one end in reinforcements in the plate sections and at the opposite end in the plate 53, as clearly shown in Figure 3. Dogs 62 and 63 are movably supported on these pivot pins and it is to be understood in this connection that while but two such dogs are shown in the upper dog unit construction, it is contemplated that any appropriate number of dogs may be used by duplicating the formation described.

The dogs 62 and 63 are of slightly difierent form, so far as their' portions in advance of the pivot pins are concerned, for a purpose which will be later explained. In rear of the pivot pins, however, the dogs are of bar-like form, as at 64, of a width to fit between the plate 53 and the plate sections 58 and 59 and of a length to overlie the limiting abutinents 60, so as to prevent or limit movement of the dogs in one direction. The bar portions 641- of the dogs are connected by. springs 65 to pins projected between the plate sections 58 and 59 and plate 53, tie springs acting to normally hold the dogs against the limit abutments 60, while permitting movement of the dogs in the opposite direction against the tension of the springs.

As the face plate opening 5 of the knee terminates short of the upper end of the knee, in order to provide the necessary rigidity of linee structure, and as it is desired that the uppermost dog of the upper dog unit be capable of ino-ving to a position coincident with the upper end of this face plate opening, said upper dog 62 forwardly of the pivot is constructed with a. portion 66 normally depending substantially in vertical line with the pivot, and with a clogging portion 67 extending forwardly of such depending portion and terminating in the usual point 63.

By this construction, the upper dog unit is permitted an increased elevation compared with that possible if the dog extended in straight line with the bar portion 6,4. The remaining dog of this upper dog unit, as 63, preferably extends in straight line with the bar portion 64, as at 69, and is provided with an appropriate clogging point 7 O. Of course, it is understood that the points proper may be of any desired form and may be integral or removably connected as may be found expedient.

As previously stated, the cylindrical base 37 of the casting of the lower dog unit receives and supports and of course seals the lower end of a cylinder 39, which extends vertically in parallel relation to the plate 53.

A piston 7]. is operative in the cylinder 39 having a piston rod 72 which extends through a suitable packed opening in a head 73 removably secured o-n the cylinder 39. rihe piston rod 72 above. the piston 7l has a diameter approximating half the diameter of the upper face of the piston, thereby mat'erially reducing the pressure area of the upper surface of the piston and constituting the respective faces of the piston of such relative areas as to provide a differential piston with respect to upper and lower pressures.

The cylinder 39 is formed at its upper end with an offset 7 t formed with a. port 75 opening into the cylinder below the upper limit of movement of the piston 71, this port having an upwardly extending by-pass 76 controlled by an upwardly opening valve 77 and leading into the upper end of the cylinder above the piston. A service pipe 78 for air under pressure is in open communication with the port 7 5.

The cylinder 39 is formed out of line with the enlargement L. with a lateral enlargement 79 formed with a longitudinally ranging passage 8O and open at the upper end to receive an air pressure pipe 81. The lower end of the passage 8O opens at 82 into the cylinder 39 above the extreme lower position of the piston 7l, the channel extending below the opening 82 and opening into the cylinder 39 at 83 below the extreme lower end of the piston, the passage between the openings 82 and 83 being provided with a ball valve Se opening in the direction of pressure from the pipe 8l.

The upper end of the piston rod 72 is removably connected to the ear 57 of the upper dog unit, so that in the reciprocation of the piston, the upper dog unit is moved longitudinally of the guide bar 7.

As stated, the upper and lower surfaces of the piston 7l constitute a differential piston, and in the operation the air under pressure is admitted through the pipe 81 and the passage 89, past the valve 84 and through the opening 83, acting to move the piston upwardly to thereby move the dog to an inoperative or non-clogging position. During this time the air under pressure is constantly delivered through the pipe 7 8 and port 75 onto the upper surface of the piston, but by reason of the reduced area of such upper surface,.the piston will move upwardly under the pressure. In the upward movement of the piston as it passes the port 75, the air above the piston will be trapped by reason of the fact that the valve 77 opens upwardly. This will form an air cushion to reduce the shock and gradually retard the upward movement of the piston.

l/Vhen it is desired to Vmove the dogs to an operative or clogging position, the air admitted thro-ugh pipe 8l is exhausted by opening said pipe to the atmosphere, whereupon the pressure through pipe 78, which as stated is continuous, operates to force the piston downwardly. The piston is cushioned at the lower end of its movement exactly in the same manner as at the upper end of such movement, as will be plain from Figure 12 of the drawings.

of the cylinder may be positioned.

propriate length rearwardly of the face plate 2 of the knee, through the dash-pot construction previously described, A `moditied resilient support may be provided through a rod 86, slidably mounted inears 87 and 88 on cylinder 39, and having a lower head 89 to bear on the bottom plate 85 of the knee. A

spring 90 encircles the rod between the head and theear 88, this spring for the `greater portion of its length being housed within a skirt 91 to therebyinsure direct actionof the spring and prevent lateral distortion thereof in operation. The plate 85 is formed in its forward portion with a slot 92 to permit the extension of the lower dog 49 therethrough.` This particular constructiony is f shown in Figure 8 ofthe drawings, and it will ibe noted that in this instance thelower. dog 49 is bolted to the plate 46 vand underlies and is secured to an extension of the `cylinder 39 or to a casting 98 in which the lower end As the motor mechanism and dogs are resilientlv supported, and as in operation, particularly in setting the upper dog, the parts move down with considerable force, it is apparent that in this movement the lower dog will, if rigid, move below its normal position. Ifthe dog were rigidly connected and in the resilient movement of the motor mechanism and dogs tended to move downwardly`r -there j would be extreme liability of the dog lenfz'asring the rack of the rack and pinion type of set works mechanis-mor a screwrrod inthe screw andV block type of set works mechanism with liability of damaeeto` the dog or to these parts ofthe mechanism. It is to be noted. howeven that the doq, that is.V the forward norti on thereof` can freely vield in the upward direction and that if. in this resilient shock absorbing movementA of thek partspthe dog` tends to contact with the rack or screw rod, the doowill yield to avoid damage to the parts. That is to sav. the dog automatically accommodates'its'elf in this movement Y topermit a full'shockY absorbing resiliency of the motor parts without liability of damage to the mechanism.

' Under the shockfahsorbing movement of the -parts as described. with the dog rigidly secured in place, damagingcontact between the dog and the set works'mechanism for the knee would probablv occur if not nrovided for. To avoid 'this interference it iS necessary to form the rack bar 94' with a slot or channel ranging` from the forward end of said `rack har for a distance-sufficient to accommodate the lower doo'. as more particularly illustrated in FigureV 7. This arrangement permits theV use of a lower dogof aD'- nrooriate form `and size in those rigs where the set works adjust the kknees through the rack and pinion method of adjustment, without disturbing the conventional relation; between the knee and rack, and therefore withoutin any way destroying the appropriate balance between the parts Vincident to the present commercial and accepted t particular operating means;

It will, therefore, be'apparent that with the lower dog mounted for independent movement or resilient movement of the parts incident to the shock, free movement is permitted without liability of damage through contact of the dog with the set works mechanism for the-knee; and that if the dog is rigidly. secured against Aindependent', movement, the rack bar of such knee setiwo'rks mechanism must be slotted to take 'care ofthe dog movement. The dog mounted for independent movement illustrates one formrof this detail and it is apparent that-such mounting to permit independent movement of the dog may be readily provided` for in a variety of ways. For example, in Figure 9 a cylindrical casting or`base for the reception of the vlower endof cylinder 39 is .indicated 'at`96 andis Ktype of this shownl as provided with antenlargement 97 overlying and of course integral with plate V46 of the lower dog unit. vThelower dog,` here shown at ,98, has thefusual dog point and a shank199 slidablv mounted in a vertically vextending bore-100 of th-e enlargement 97. The'V upper end .of rvthe Yshank 99 has a head 101 tolimit the downwardv movement of the dog-while the Vrelation of the dog'and bore lin' which itV slidesis such thatthendog may l,yield upwardlyindependently of thev lowervdog unit to permit the full resilient shock absorbing movement of the parts lwithout liability of damage through contact'of the dog with the set works mechanism 'of lthe knee.V

- From the above description itiwill be'apparent that` asidei from .the 4resilient support provided through the dash-pot or the` rod 58.' the entire doe!v mechanism and dog operating means is carred by the guide bar7,

and that the latter is movable toward and from the fa oe of the knee through the power mechanism included in the cylinder 15, which latter is arranged beyond and at one side of the knee. In order to accommodate the guide bar and doa' carrying unitst and particularlv to permit the necessary play of the guide bar in its 'adjusting movement, it may be found necessary to slightly increase the distance between the side vwalls-4 of the knee comnared with the-conventional spacing of these walls. and if desired such walls may `he laterally deflected, as indicated at 102 =in Figure Under these circumstances. it will be found necessary to provide additional snare for the iolav of the lower'crank 9 in or" der to permit the gui de bar to be moved to the desired limit toward the face of the knee` and if1 such is required, the wall 4 adjacent the iso crank will be olset, as at 103, throughout an appropriate area to permit the desired throw of the crank.

In operation, the guide bar 7 and therefore the upper and lower dog units and connected parts may be adjusted relative to the face of the knee by appropriate control of the piston within the cylinder 15, this operation simultaneously Vshitting the cranks 9 about the cra-nk shafts lO as a center, and correspondingly moving the guide bar 7 bodily relative to the face of the knee. As the upper and lower dog units are carried by the guide bar, the dogs will be correspondingly projected relative to the face of the knee. This then provides for securing the desired projection of the dogs. In the normal positions of the respective dog units, the upper dog unit is at its maximum elevation, that is, the piston 7l will be substantially at the upper end of the cylinder 39. Jassuming it desirable to engage a log, pressure is controlled as described to force the piston 7l downwardly. This causes the upper dog unit to move downwardly on the guide bar 7 until such movement is interrupted by the appropriate dog of the upper dog unit engaging the 10g, cant or board, as the case may be. In this move-` ment, it will be obvious that as the dog engages the material, movement of thedog in a direction resulting from such engagement is impossible, as the "dog bears against the dog limiting abutment 60, hence 'for operative movement the dog may be said to be inimovable. As the appropriate upper dog engages the material, movement of the piston is of course interrupted, and the continued admission of pressure to the cylinder 39 will at once result in causing the cylinder to become the movable element and the piston the fixed element. Thereupon the cylinder will move upwardly, and as the cylinder is in etfect a fixed part of the lower dog unit, the lower dog will, in such movement of the cylinder, be moved upwardly to engage the lower surface of the log, cant or board. 75th the pressure maintained, the dogs are held in gripping relation in the material and the sawing or other operation may be proceeded with;

It is to be particularly noted that, as previously described, the free or outer surface of the flange 56 and the corresponding surfaces 4 of the plate sections 58 and 59 form an abutment to resist play of the cylinder in a direction toward the guide bar 7. It is evident that as the parts are moved to operative position, they will of necessity engage the material with considerable force, causing a sud-- den interruption of the movement oi the parts with a consequent tendency to :torce the cylinder toward the guide bar.V It such movement of the cylinder was permitted, a distortion of the arrangei'nent would eventually result with loss of eciency, and hence the abutment described is provided as a substantially fixed wall to restrict any such play of the cylinder and insure a. proper relative disposition of the parts under any ordinary working strains and stresses.

It will be noted that the dogs are preferably though not necessarily so constructed that at the maximum inward adjustment of the guide bar, the points of the dogs will still project to some extent beyond the face of the knee. This minimum projection has its advantages, in that when the guide bar has been adjusted to its inner position, there is still a dog projection which will serve to engage a board, whereas if the inner limit of adjustment of the guide bar was such as to withdraw the dogs wholly within the tace of the knee, that disposition of the dogs necessary to engage a board would require an intermediate position of the guide bar, and thus necessitate more or less care in such adjustment which is entirely eliminated by having the inner limit of the guide bar adjustment position the dogs for board engagement. This normal projection of the dogs is without any disadvantage from the standpoint of possible damage to the dogs by being engaged by a log rolled against the knee, for it will be apparent that the dogs under such impact can readily yield against the tension of the springs and thus any possible damage t0 the dog points is entirely avoided.

What I claim to be new is:

l. In a saw mill carriage, a knee, a guide bar relatively movable toward and from the face of the knee, a lower dog unit slidable on the guide bar, an upper dog unit slidable on the guide bar, a cylinder carried by the lower dog unit, and a piston operative within the cylinder and connected to the upper dog unit, sai d upper dog unit being formed to provide an abutment to limit undue play ofthe cylinder in one direction in the operation of the parts.

2. In a saw mill carriage, a hollow knee` upper and lower dog mechanisms mounted within said knee and including a guide bar movable toward and from the knee face, an upper dog carrying unit slidable on the guide bar, a lower dog carrying unit slidable on the guide bar, a cylinder carried by said unit. a piston operative within the cylinder and connected to the upper dog unit, and cushioning means depending from the lower dog pnit and adapted to engage the base of the mee.

`3. In a saw mill carriage, a knee, a guide bar movable relative to the face of the knee, a

lower dog unit slidable on the guide bar. a

motormechanism carried by the lower dog unit and includinga cylinder, and an upper dog unit including a plate formed with flanges to slidably embrace the guide bar, said plate on the edgenext the cylinder being formed with a flange to provide a limiting abutment for the movement ot the cylinder.

l. In a saw mill carriage, a knee, a. guide bar arranged within the knee and movable relatively to the face of the knee, an upper dog unit slidable on the guide bar, a dog carried by said unit, a lower dog unit including a plate formed with flanges to slidably embrace the guide bar, a motor mechanism for the respective dog units including a cylinder` connected to said plate, and a lower dog carried. by the plate.

5. In a saw mill carriage, a knee, rack and pinion mechanism for operating the knee, a guide bar arranged within and operative relative to the face oi the knee, an upper dog unit slidable on the guide bar, a lower dog unit slidable on the guide bar, motor mechaanism :tor operating the dog units, and a support to absorb the shock of operation of tho motor mechanism on the underlying parts of the setworks, without damaging contact o'f the lower dog therewith in the shock absorb'- ing movement of the parts.

6. Vln a saw mill carriage, a knee, a means for operating theknee, a dogging mechanisn arranged in the knee including a guide bar, an upper dog slidable Von the guide bar, a lower dog slidable on the guide bar, a motor mechanism for operating the dogs, and a support between the motor mechanism and knee to gradually absorb the shock of motor mechanism operation, the parts being arranged so that the 'damaging' contact of lower dog is avoided in the play incident to the shock-absorbing tunction of the support.

7. ln a saw mill carriage, a knee including a divided face plate, spaced side walls', and a rear wallconnecting the side walls, whereby the knee provides a hollow chamber in rear of the face plate and communicating with the division in the latter, a guide bar arranged in saidl hollow chamber ofthe knee andmovable toward and from the face plate, meanslior operating the guide bar', an upper dog slidable on the guide bar within the hollow chamber of the knee, a lower dog slidable on the guide bar within the hollow chamber 'of the knee, said dogs being operable through the division in the tace plate in the movement ofthe guide bar, and a motor mechanism arranged in the hollow chamber' of the knee and connected to and adapted to operate the upper and lower dogs in succession.

8. In a saw mill carriage, a knee including a. face plate and spaced side walls extending rearwardly therefrom, a guide bar extending substantially parallel with the faceplate and movably supported Von one ot said side walls and operable toward'and from' the i'ace of the knee, an upper dog slidable on'the guide bar, a lower dog slidable on the 'guide bar, and a motor mechanism vfor operating the dogs in succession, said motor mechanismincluding a cylinder arranged in substantial parallel- 'l ism with and adjacent the guide bar and-conV nected to one-of the dogs and a piston operating in the cylinder and connected to the other of the dogs. v

9. ln a saw mill carriage, a knee including a face plate and spaced side walls extending rearwardly therefrom, a guide bar extending in substantial parallelism with the face plate and movably supported on one of the side walls of the knee, motor mechanismlcarried by the knee beyond the side walls and operativelyzconnectedto the guide bar for the actuation of the latter, an upper dog slidable on the guide bar, a lower dog slidable 0n the guide bar, and fluid pressure means for operating the dogs in succession, said 'fluid presv snre means including a cylinder arranged in substantial parallelism with an immediately adjacent the guide bar and operatively connected toy one ofthe dogsv and a piston operative in said cylinder and directly connected `including a cylinder arranged in substantial parallelism with the guide bar and immedi# ately adjacent thereto, said cylinder being operatively connected to one ofthe dogs, the

piston in the Icylinder operatively connected to the other of said dogs, and means to cushion the motor mechanism and thereby the dogs relative to the knee. i

l1. In combination with the knee ,of a saw mill carriage, said knee including va face plate, sidewalls exten'ling rearwardly from the'iace plate in spaced relation, and a4 bed plate bridging the sidewalls at their lowerends, lclogging mechanism arranged wholly betweenthe side walls of the knee and above the bed plate and including a guide barmovable toward andirom the face of the knee, pper and lower dogs independently. slidable on the guidefbar, and motor mechanism car ried by and movable with the guide bar and involving relatively movable elements inde! pendently connected to the respective dogs, and means for cushioning the clogging mech-l anism onthe bed plate ofthe knee, and a set. works element cooperating with`A the knee, said element being slotted to permit non-inr terfering play 'of the lower dog in the cushioned movement of the clogging mechanism. l2. In combination, aknee for saw; mill carriages includingspaced hollow side walls and a divided tace plate, a set works member cooperating withl theknee lfor taper adjust'- ment of the latter, and clogging mechanism supported wholly between the side walls of the knee and including dogs bodily adjustable toward and from the face of the knee and independently movable vertically of the knee, means for cushioning the clogging mechanism to cushion its action, the set works member being longitudinally slotted in line with one of the dogs to permit the free non-interfering play of that dog in the movement of the clogging mechanism incident to its cushioned action.

13. In a saw mill carriage, a knee including a face plate, side walls extending rearwardly therefrom in relatively spaced relation, a guide bar movably supported on one of the side Walls and operable toward and from the face plate, an upper clog casting slidable on the guide bar, an upper dog pivotally supported on said casting, a lower dog casting slidable on the guide bar, a lower dogI carried by said lower dog casting, a cylinder directly supported by the lower dog casting and extending immediately adjacent and in substantial parallelism to the guide bar, a piston operative within the cylinder and directly connected to the upper dog casting, and means for admitting' fluid pressure to the cylinder.

14. In a saw mill carriage, a knee including a face plate, side walls extending rearwardly therefrom in relatively spaced relation, a guide bar movably supported on one of the side walls and operable toward and from the face plate, a guide plate overlying and bearing against one surface of the guide bar and :onnected to the guide bar for sliding cooperation therewith, independent dogs pivotally supported on said guide plate, a lower dog casting slidable on the guide bar, a dog carried by the lower dos: casting, a cylinder sunported in said casting and extending in substantial parallelism to the guide bar and ad] acent thereto, and a piston operative within the cylinder and connected to the guide plate abovethe dogs carried thereby.

15. Ina saw mill carriage, a knee including a face plate, side walls extending rearwardly therefrom in relatively spaced relation, a guide bar movably supported on one of the side walls and operable toward and from the face plate, a guide plate overlying` and bearing' against one surface of the gui de bar and connected to the guide bar for sliding' cooperation therewith, independent dogs pivotallv supported on said guide plate. means carried bv the guide plate for pivotal movement-s of the dogs in one direction, a. lower dog casting slidable on the guide bar. a dogA carried bv the lower dog casting. a cvlinder supported by said casting and extending in substantial parallelism to the guide bar and adjacent thereto, and a piston operative within the cylinder and connected to the guide plate above the dogs carried thereby.

16. In a saw mill carriage, a knee, a guide bar movablerelative to the face of the knee, upper and lower dog units mounted on the bar, means for supporting the bar for movement toward and from the face of the knee, said means including a crank shaft having' bearing in the knee, radial arms at the respective ends of the shaft, and a crank pin anchored in the guide bar and bearing in the free ends of the arms, said crank shaft and radial arms being formed as an integral member, means connecting similar crank arms to compel unit movement, and fluid pressure means connected to one of the crank arms for operating the same.

17. In a saw mill carriage, a knee, a guide bar movable relative to the face of the knee, upper and lower dog units mounted. on the ar, means for supporting the bar for movement toward and-from the face of the k ce, said means including crank shafts having bearing in the knee, inner crank arms projecting from the shafts, outer crank arms of right angled form projecting from the shafts, crank pins anchored in the bar and having bearing in the similar crank arms at the respective ends of the shafts, said crank shaft and crank arms being formed as an integral unit. and means for operating the crank arms simultaneously.

18. In a saw mill carriaae. a knee. a guide bar movable relative to the face of the knee, upper and lower dog units mounted on the bar, means for supporting the bar for movement toward and from the face of the knee, said means including crank shafts having bearing in the knee. inner crank arms projecting from the shafts. outer crank arms of right angled form projecting from the shafts, one of the crank pins bein;r anchored in the bar and having bearing in the similar crank arms at the respective ends of the shafts, said crank shaft and crank arms being formed as an integral unit, terminal nuts for the anchored crank pins to compensate for wear in the connection. and means for operating the crank arms simultaneously.

19. In a saw mill carriage. a knee. a guide bar movable relative to the face of the knee, upper and lower dog' units mounted on the bar, means for supporting the bar for movement toward and from the face of the knee. and a motor mechanism for operating said means. said mot-or mechanism including a differenti al cylinder` differential. pistons operative in the cylinder, piston rod intermediate said pistons and said means. and a motive fluid un der pressure for controlling the move` ment of the pistons, said pistons acting as seals in their limit positions.

20. rlhe combination with a knee, of a @luide member thereon. a dog carrier vertically rnovahle with respectv to the guide member, a plurality of d ogs pivotallv mounted on the dog carrier, abutments on the dog carrier to imit the movement of the dogs on their pivots in a directionV toV maintain the points of the dogs in operative position, and means whereby the dogs may be influenced to contact with said abutments, said logs` being w freely movable in a direction away from said. abutments to permit the operative ends of the dogs to move under knee impact to avoid breakage of the dogs. Y e

In testimony whereof I aiiix my signature. y

GEORGE M. PELTON.l 

